Computer databases or similar constructions (hereinafter referred to as data stores) are powerful tools for storage, organization, retrieval and other handling of various types of information. However, there are different database models, or formats, for data access that are incompatible with each other, and may also be incompatible with, or remarkably different from, an object programming application. In this respect, complex relationships between objects present in the object programming application may be entirely absent in a relational or object database being accessed or updated. Nonetheless, a plurality of these database types have achieved a high level of popularity and proliferation. The two most common database models are object and relational, and object programming models are frequently used for internet applications involving database accessing.
As an example of common object programming applications, the popular Java language with its server-side component, Enterprise Java Beans, is being widely used to support object model programming applications that access and use data from databases that have a JDBC driver. Thus, it is desirable to be able to adapt and use many of the traditional relational database tools, utilities, systems and corporate procedures with the newer object format of many more recent web-based applications. Since many users may be accessing a single application, there is a need for speeding up database accesses and for synchronizing object programming application transactions with database accesses and updates.
Systems for accessing data storage based upon objects have been used for many years to accommodate object-directed software applications. The most common conventional approach to accomplish access of data stores involves writing and imbedding custom access codes within an object application needing access to the data. This approach is generally limited to having custom codes capable of accessing only a single relational table within a relational database or similar construction, referred to as a data store. When an object model has been adapted specifically for accessing a single data store using the JDBC driver for that data store, moving data to a second database or accessing multiple databases can become very problematic and painful for a programming engineer who is assigned the responsibility for such a task.
The aforementioned conventional approach to bridging between object and relational models (or between object and multiple relational models) has frequently required “brute-force” hand-recoding of relational database access code. This approach can be very time-consuming and is prone to errors. This approach can also generate inefficient objects that require more processing time, storage space, and transfer time. Further, this approach does not scale well because each instance of relational access code must be converted manually, in turn, even if similar objects have already been applied for use with the converted relational data base.
As mentioned above, more efficient approaches sometimes use tools to automate the conversion process. However, the tools provided to date typically are not versatile enough to handle many types of conversion without manual coding or explicit defining of parameters by a human operator. Because of this requirement for operator participation in the translation, the conversion using today's tools still does not scale well and does not allow for fully automated and flexible conversion of data access between various data base models.
Further, this approach to conversions does not provide for communicating the conversions in an efficient manner as, for example, to other entities who may need the same type of conversion on similar data, or who may require the conversion to access the data in another way. In a distributed environment that may involve multiple users accessing multiple databases by multiple object applications, this can get exceeding complex. Another drawback of conventional systems and techniques (as understood in the conventional art), is that dynamic mapping of objects to multiple types of databases is virtually impossible, because the tailored hand code must be updated and recompiled. This may require that an application be stopped and restarted in order to implement mapping changes, i.e., the mapping changes are not dynamic.
Significant drawbacks are associated with using a relational database model in conjunction with an object programming model, but the relational database model is still the most widely accepted traditional format for reliable and quick access to data while using complex data search queries. This model allows the user to store data records and to access the data via a query language that uses relational expressions such as AND, OR, NOT, etc. Over the years, the vast majority of production databases have been relational databases, each having its own relational arrangement, and accessible by a particular query language. While convenient for set-up and arranging data, access is had only by those having substantial knowledge of the various relationships between pieces of data in the database.
JDBC drivers have been designed to formulate database specific SQL queries or statements from standard SQL strings passed to them by an object programming application. Ordinarily, such JDBC drivers are specific to a database, and separate statements and separate JDBC drivers must be utilized to access different databases. This is complicated by the fact that many object programming applications either do not permit simultaneous attachment to multiple databases or poorly coordinate transactions that impact multiple databases. Accordingly, relational databases can sometimes be awkward to access, and transferring data from one database to another database can be slow and painful, unless a specific transfer program has been specifically written or tailored to effect that specific transfer of data.
The object database model is a newer model that has rapidly increased in usage due to recent trends such as the world-wide-web and application service provider (ASP) architectures. Such object databases have sometimes been used as the primary source for accessing data, for example, Jasmine and ObjectStore are available from Computer Associates Intl., Inc. and Object Design Inc. (ODI), respectively. However, accessing data in such permanently stored object database has raised serious performance issues for larger applications when complex querying is required (as compared to relational databases). Complex querying is usually faster using relational databases since query engines may be more highly developed for relational database accesses.
Previously, object applications have tended to only use simple memory buffers with relational and object databases. Difficulties existed with using either an object database or a relational database to serve as a transient memory resident database “cache” (secondary database) to try to speed up database accesses. No commercially viable solutions have existed with acceptable performance.
There is a need for an object programming application to successfully access a secondary transient memory resident database, as either a relational database or an object database. In such a case, a dynamic database mapping tool would be necessary to provide the object programming application with a map or maps to both the primary and secondary databases in order to successfully implement a dynamic transient memory resident database. It would be particularly helpful in optimizing the performance of an object programming application if there could be provide a memory resident object database (or a resident portion thereof) as a cache for data retrieval. In such a case it might be possible to directly access (and perhaps re-use) data objects stored in the secondary transient resident memory database, including their metadata, instead of generating data objects from accessed data.
If it were possible to successfully provide a commercially viable secondary memory resident transient database, data being used by the object programming application would only need to be persisted back to one or more of a permanent storage relational database (primary database) when data has been created, inserted or updated. Ideally, the application would likewise update the memory resident object database (secondary database) when the primary database is updated. However, as mentioned such simultaneous access of multiple databases can give rise to transactional coordination problems, or to data synchronization problems.
Accordingly, intensely needed by many modem software application programs are systems for more efficient access and manipulation of data stores, systems having the flexibility and dynamic capability to attach data from a database to maps as objects and having the ability to map one or more databases to various objects in real time. A strong need exists for such systems that also permit a user to cleanly, transparently and synchronically transfer data between multiple data sources, while maintaining the ability for an object programming application to access or use such data in the system. The need exists for an improved database access buffering system, for object programming applications, having at least one transparent secondary memory resident database and a primary data source that can be simultaneously utilized in a synchronized and transaction coordinated manner.